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10/03/2010

The Value-Added Teacher Reform Program—Posner

There is widespread concern that elementary and secondary school education in the United States is deteriorating and is now inferior to that of many other countries, as measured for example by high-school graduation rates and college attendance rates. Proposals for reform fall into two main classes: increasing competition in the provision of educational services; improving the quality of public school teachers.

A reform aimed at improving the quality of public school teachers that has received a good deal of attention lately is the “value added” method of evaluating teachers’ performance, now being used in the public schools of Los Angeles. See “Grading the Teachers: Value-Added Analysis,” www.latimes.com/news/local/teachers-investigation/. The evaluation begins with determining the average improvement of a student, say between the end of third grade and the end of fourth grade, and then comparing the student’s actual improvement, all as measured by performance on standardized tests. If his or her improvement is above the average improvements, the teacher is rewarded, for example with a bonus; if below, the teacher can be counseled in an effort to improve the teacher’s performance. The Secretary of Education, Arne Duncan, supports value-added teacher evaluations (and informing parents of the teachers’ scores); the teachers’ unions oppose it as a step toward merit-based pay of public school teachers or even elimination of tenure.

The main objection to the program is that the value added by a teacher can’t really be measured. The reason is that much may influence a student’s performance (including his year-to-year improvement) besides the teacher, including fellow students, conditions at home, and the student’s intelligence and application. These other factors could in principle be controlled for, but actually to do so would probably strain the ability of public school bureaucracies to devise and administer sophisticated statistical measurements. The alternative would be to assume that differences across students average out. But unless classes are very large and students are assigned to teachers randomly, differences in average performance are unlikely to be statistically robust.

The value-added methodology is, moreover, very difficult to apply beyond elementary school. When students have more than one teacher at a time their progression from year to year is the result of a team effort, and it is difficult to identify the contribution of each teacher. Even if improvement (or lack thereof) is measured on a subject-by-subject basis, the existence of complementarities between subjects (math and science, for example, or history and social studies) means that a teacher in one subject can influence student performance in another. And the complementaries can be subtle: an excellent English teacher may inspire her students with enthusiasm for school in general, stimulating them to improve their academic performance in unrelated courses.

Even with all these difficulties acknowledged, the granting of bonuses to teachers who receive above-average value-added evaluations would have some good effect on teachers’ motivation. But of course the money has to come from somewhere, and the benefit may not equal the cost. It is doubtful, moreover, that value-added evaluations, even when publicized (as the Los Angeles Times did recently with the L.A. public schoolteacher evaluations, causing a good deal of commotion and, it seems, the suicide of one teacher), have much effect on bad teachers, either by causing them to improve or by easing them out of the system. The methodology is too crude (and likely to remain so) to provide a solid basis for censure, self-criticism, instituting a system of merit pay, or ending teacher tenure. Tenure has of course bad effects, whether it’s tenure in public or private schools, in public or private universities, in the federal judiciary, or unionized workplaces: it encourages slacking off, selects for people who have a high degree of leisure preference, and leads to retention of poor performers. At the same time, however, it is a form of compensation valued by many; were it eliminated in public schools, the schools would have to pay higher, maybe much higher, salaries, which hardly seems feasible in today’s economic climate (which is likely to be tomorrow’s too).

So value-added evaluation of public schoolteachers, while ingenious (despite its limitations) and growing in popularity, does not seem to be the answer, or even a major part of the answer, to dissatisfaction with American education. Competition is more promising. Two forms should be distinguished: charter schools, which are public schools (that is, publicly financed and tuition free) that are however managed outside the normal public school system in order to enable and encourage experimentation; and means-tested vouchers, which are scholarships that a student can use to attend a private (including parochial) school. About a million students are enrolled in charter schools, and 200,000 other students receive vouchers enabling them to attend private schools. Home schooling is another alternative to public schools, and an important form of competitive education, but it is not feasible for students from poor homes because their parents (often just a mother) rarely have enough education for them to able to teach their children.

The charter schools have turned out to be a mixed bag. There is excess demand for them, which is some evidence that they are superior to public schools. But studies of drop-out rates and other measures of quality indicate that while some charter schools are indeed better than public schools, many are worse; there is as yet no convincing evidence that on balance they are superior to public schools. There is more evidence that vouchers improve educational performance, though it is not conclusive. See “Is School Choice Enough?”www.city-journal.org/2008/forum0124.html. Vouchers enable poor students to attend established schools with a proven record of quality (many of these are Catholic parochial schools), so it is not surprising that they are more effective in improving academic performance than conversion of existing public schools to quasi-private status, which is the character of the charter-school movement.

Teachers’ unions are more fiercely opposed to vouchers than to charter schools, which is a vote in favor of vouchers! Private schools have greater freedom from regulation and are less likely to be unionized than charter schools (although charter schools, too, are generally not required to bargain collectively with their teachers), and they are numerous and established and can expand to accommodate increased demand.

I favor vouchers, but they are no panacea. Obviously, basic education is an important social good. But even bad schools provide that. How much value good schools can add to the skills and knowledge of students who now attend bad schools is uncertain. Maybe most students who attend bad schools have limited aptitude and motivation because of low IQ, poor physical or mental health, peer-group pressures, a bad family environment, or effects of popular culture. How far such impediments to academic performance can be remedied by teachers, however skilled, and at what cost, is unclear to me.

Well, perhaps with a combination of vouchers and competition schools could specialize in dealing with kids who are disadvantaged. Assuming their parents have the insight to select the right school for them, but still offering the choice to opt out of a clearly broken system seems much more likely to help than hurt.

Thank you for responsibly acknowledging you are "unclear" with regard to these issues. That is the only fact of any note in your article. Obviously, neither you nor Mr. Becker are experts. Nor is Arnie Duncan, unfortunately. Is it a "broken system" as so many assert? The public schools seem to be on a much sounder footing than many other aspects of our society, including every branch of the Illinois and federal governments. Criminal wars, corruption, endless budget deficits, fiat money, forced support for the criminal religious enclave of Israel, how do these politicians believe they have any credibility on any subject? I am the proud product of the public schools. I would defend every one of my elementary and high school teachers. It was only after graduating from high school and attending college and professional schools that I came into contact with REAL incompetence and unmotivated teachers. Fortunately, they did not affect my achievement since I was otherwise well motivated and prepared. MAYBE ELEMENTARY AND SECONDARY SCHOOL TEACHERS WOULD LIKE TO COMMENT ON THE FEDERAL COURTS, IVY LEAGUE SCHOOLS, ECONOMICS AND THE MORAL AND ECONOMIC BANKRUPTCY OF AMERICAN GOVERNMENT IN THE TWENTY FIRST CENTURY. THEY WOULD BE AT LEAST AS WELL QUALIFIED, AND IN SOME CASES, MORE QUALIFIED.

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Another problem is that how much a student improves depends on the student's room for improvement. Imagine a teacher given a class of student s who score 100% A+ on everything. That teacher couldn't improve the students at all. Moreover, you'd get a situation where if the teacher that the students had last year improved them too much, the teacher they have this year will find it unreasonably difficult to make further improvements.

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The public schools seem to be on a much sounder footing than many other aspects of our society, including every branch of the Illinois and federal governments. Criminal wars, corruption, endless budget deficits, fiat money, forced support for the criminal religious enclave of Israel, how do these politicians believe they have any credibility on any subject? I am the proud product of the public schools. I would defend every one of my elementary and high school teachers.

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you'd get a situation where if the teacher that the students had last year improved them too much, the teacher they have this year will find it unreasonably difficult to make further improvements!
yes,maybe right!

Compare the error rates for VAM reported by LA Times against those by publishing scholars. Then compare the reported methodologies.

The LA Times claims to be more accurate than anyone else, yet provides less information about the statistical innovations which allow them to make such a claim. In fact, the LA Times claims suspiciously low error rates (compared to the state of the art) and has not disclosed their method sufficient to allow verification of their results.

Yet here is Professor Posner making references to that dubious study twice, without a single link to reputable scholarly works. How odd.

"Economists" and others try to make a case for merit pay, "value added" pay or even "vouchers" in an attempt to wring more, difficult to measure performance from the existing teaching staff.

Left out of the discussion is the fact that the US is short some 50,000 teachers. Now why are we short of teachers? Should be an easy question for the supply and demand set; that despite the personal rewards of teaching wages are generally too low to create strong competition for the "best and brightest" college graduates............ Ha! many of whom go on to Wall Street where they prey on us in order to become youthful millionaires and generate a family fortune.

Many education "worriers", Posner included are strongly opposed to the unions and collective bargaining, apparently as they'd rather beat down salaries and working conditions yet further despite US teacher salaries lagging behind those of many other nations.

While some will point out high salaries alone do not assure us of quality and wisdom (Wall Street comes quickly to mind) surely all "supply and demand" folk will have to agree that were teacher pay high enough to create competition for the jobs and to, if not actually provide a living std similar to that of other professionals, at least one that is a few notches above the poverty line.

It doesn't take much imagination or much economic training to understand that in a nation short of teachers the tendency to keep what staff they have and hire less than the best will be strong.

Crucial factors in educational performance are the intelligence and motivation of students along with the family structure they live in. No reform of the educational system can overcome these factors if they are poor. Attempts to equalize educational opportunities has only served to drag down the development of the most gifted students coming from the best families. Consider the research on this issue by Robert Weissberg in his *Bad Students, Not Bad Schools,* Transaction Publishers, 2010.

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